lib-src/strings/kr.cc

   1 //////////////////////////////////////////////////////////////////////////////
   2 // NOTICE:
   3 //
   4 // ADLib, Prop and their related set of tools and documentation are in the
   5 // public domain.   The author(s) of this software reserve no copyrights on
   6 // the source code and any code generated using the tools.  You are encouraged
   7 // to use ADLib and Prop to develop software, in both academic and commercial
   8 // settings, and are free to incorporate any part of ADLib and Prop into
   9 // your programs.
  10 //
  11 // Although you are under no obligation to do so, we strongly recommend that
  12 // you give away all software developed using our tools.
  13 //
  14 // We also ask that credit be given to us when ADLib and/or Prop are used in
  15 // your programs, and that this notice be preserved intact in all the source
  16 // code.
  17 //
  18 // This software is still under development and we welcome any suggestions
  19 // and help from the users.
  20 //
  21 // Allen Leung
  22 // 1994
  23 //////////////////////////////////////////////////////////////////////////////
  24
  25 #include <stddef.h>
  26 #include <string.h>
  27 #include <AD/strings/kr.h>
  28
  29 void KR::compile (const char * pat, int len)
  30 {  if (len < 0) len = strlen(pat);
  31    patternLength = len;
  32    delete [] pattern;
  33    pattern = new char [len];
  34    memcpy(pattern,pat,len);
  35    fingerPrint = 0;
  36    for (register int i = len-1; i >= 0; i--) fingerPrint += pat[i];
  37 }
  38
  39 int KR::Match(register const char * text, register int length) const
  40 {  if (length < 0) length = strlen(text);
  41    if (length < patternLength) return -1;
  42    register int i, j;
  43    register unsigned int chi = 0;
  44    for (i = 0; i < patternLength; i++) chi += text[i];
  45    for (j = 0; ; i++, j++) {
  46       if (chi == fingerPrint &&
  47           memcmp(pattern,text+j,patternLength) == 0)
  48           return j;
  49       if (i >= length) break;
  50       chi += text[i] - text[j];
  51    }
  52    return -1;
  53 }